The invention relates to a method for automatically adapting vehicle lighting to a surrounding area of a vehicle, particularly when road signs are present in the surroundings of the vehicle, as well as to a lighting apparatus for a vehicle that is suitable for illuminating road signs.
During night driving, a lighting apparatus of a vehicle is particularly important for a driver with respect to safety and driving comfort. High-beam assistance systems (FLA) already permit a selective and adaptive illumination of the road. However, the previously known high-beam assistance systems offer no functionality for protecting a driver from an unpleasant and dangerous blinding as a result of a strong reflection of light from road signs. Particularly during night driving with high-beam headlights, a reflection of the vehicle's own light from road signs may result in severe blinding and thereby in a high-risk impeding of the driver's view.
In the case of blinding as a result of the reflection of the vehicle's own light from road signs, a driver currently can only reduce or limit the blinding by way of manual changes of the light, for example, by switching to low-beam light. High-beam assistance systems known so far offer no functionality for relieving the driver from this operating step. Instead, high-beam assistance systems provide information as to whether, for example, an oncoming vehicle or a vehicle driving ahead is present in the surroundings of the own vehicle or whether the own vehicle is situated in an illuminated town. This information provided by a high-beam assistance system permits only an automated deactivating of the high-beam light for scenarios with oncoming vehicles or vehicles driving ahead or in illuminated towns.
The blinding of a driver by the reflection of light at road signs is not only perceived to be annoying by the driver. Glare also represents an increased danger potential during night driving when the accident potential already is particularly high because of limited visibility, crossing deer or slipperiness. A driver's blinding by high-beam reflection at a road sign may lead to a late or wrong reaction in dangerous situations. A manual switching-over from high-beam to low-beam light is time-consuming, which has the effect that the blinding will in fact last longer. On the other hand, an excessive prolonged deactivating of the high-beam also leads to an increased risk because the illumination of the road will no longer be optimal during that time period.
It is desirable to provide a method for automatically adapting vehicle lighting to a surrounding area of the vehicle by which reflections of the own vehicle's light at road signs can be avoided or at least largely reduced. Furthermore, there is the need to provide a lighting apparatus for a vehicle which makes it possible to avoid or at least largely reduce the reflection of the own vehicle's light at road signs.
An embodiment of a method for controlling vehicle lighting includes the following steps:
lighting the surroundings of the vehicle by way of a lighting device of the vehicle,
acquiring an image of the surroundings of vehicle,
determining whether a road sign is present in the surroundings of the vehicle,
detecting a position of the road sign in the surroundings of the vehicle by analyzing the image if it is determined that the road sign is present in the surroundings of the vehicle, and
changing a light, which is emitted by the lighting device of the vehicle, in the direction of the detected position of the road sign in the surroundings of the vehicle such that a reflection of the emitted light at the road sign is reduced if it has been determined that a road sign is present in the surroundings of the vehicle.
According to the suggested method, when driving in the dark, if a considerable reflection of the light of the own vehicle is occurring at the road signs, the lighting is adapted in an automated manner by way of a high-beam assistance such that the reflection is reduced and the driver is therefore no longer significantly blinded. This leads to a higher driving comfort and to higher safety. An increased blinding of a driver, which is a result of the fact that road signs with a very high reflectance guide light from the headlight back to the driver's eye, can be reduced by way of a targeted, possibly partial reduction of the headlight brightness.
According to a conceivable embodiment, an image of the illuminated surroundings of the vehicle can be acquired for this purpose. In the acquired image, dominant radiation sources can be located and can be classified with respect to reflection. Besides or in addition, a road sign detection can be utilized. Such a road sign detection may, for example, be provided by currently already customary camera-based driving assistance systems. Such camera-based driving assistance systems, as a rule, simultaneously have several functionalities. In addition to a light detection for the automatic activation/deactivation of the high-beam light and the adaptive control of the light distribution, a detection of road signs is often also present. This road sign detection is used, for example, for indicating the currently valid speed limit to the driver.
By way of such a road sign detection, for example, the following features can be detected: class of sign, size of sign, reflectance, type of sign and the position of the sign relative to a vehicle coordinate system. The type of the sign and the position of the sign relative to the coordinate system of the vehicle can be recognized, for example, by a camera installed in the vehicle. By way of a brightness value in the image, the reflectance can also be determined when the brightness of the surroundings and the brightness of the headlights of the vehicle are known. By way of this information, the vehicle headlight can be activated in a targeted manner such that the brightness of the lighting of the own vehicle is reduced in a targeted manner precisely in the position in which the road sign is situated in the scene of the surroundings.
The lighting device of the vehicle, such as the vehicle headlight, can be activated such that the full brightness of the headlight is maintained in the remaining surroundings and on the road, so that the driver's view will not be impeded. Instead, a road sign standing at the edge of the road will now only be illuminated with a low light intensity of the headlight. The light emitted by the lighting device in the direction of the road sign is therefore changed in a targeted manner or is reduced in its brightness. The road sign therefore no longer appears so bright to the driver and a glare from the road sign is clearly reduced, whereas the remaining scene continues to be illuminated at full light intensity.
A corresponding embodiment of a lighting apparatus for a vehicle includes a lighting device for emitting light for the lighting of an area surrounding the vehicle, an acquisition device for acquiring an image of the surroundings of the vehicle, an analyzing device for determining whether a road sign is present in the surroundings of the vehicle, and a control device for controlling the lighting device of the vehicle. The analyzing device is configured to determine a position of the road sign in the surroundings of the vehicle by analyzing the image. The control device is configured to control the lighting device such that light emitted by the lighting device in the direction of the road sign is changed, whereby a reflection of the emitted light at the road sign is reduced.
By way of such a method and lighting apparatus, the driving comfort can be increased during night and evening driving. Furthermore, driving safety is increased and the accident risk is reduced because the lighting apparatus switches faster and more effectively than a person. In particular, the lighting is switched back more rapidly to full brightness, and thereby an optimal utilization of the high-beam takes place. In combination with a corresponding headlight system, for example, a matrix headlight, the manufacturing costs of the lighting apparatus are comparatively low and there is no significant weight increase.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.